Commonly known as the roof rat, ship rat or house rat, the black rat, Rattus rattus, likely came from tropical Asia, and then was spread around the world by humans-first by the Romans and later by European colonists.
Blamed for disease and pestilence such as the Black Death, a recent study published by the National Academy of Sciences, suggests the rat has gotten a bad rap.
It was previously believed that the bacteria, Yersinia pestis, responsible for the Black Death, was found on the black rats and that the bacteria was transmitted from the rats to fleas which then transmitted them to humans. Researchers now believe the responsible rodent was a Central Asian giant gerbil and that the plague showed up at port cities in Europe when there was a burst of population growth among the gerbils due to favorable climate conditions.